[php-src] PR #23946: ext/spl: Use fast ZPP in hot ArrayObject and ArrayIterator methods

Pull Request: https://github.com/php/php-src/pull/23946 Author: nicolas-grekas return new \ArrayIterator($this->items); is the usual getIterator() implementation of Twig nodes, Symfony bags or Doctrine collections, and profiling a foreach over such objects shows zend_parse_parameters() taking about 180 instructions per ArrayIterator::__construct() call. This switches both constructors and the ArrayAccess methods (offsetExists(), offsetGet(), offsetSet(), offsetUnset(), append()) to fast ZPP. Accepted types, error messages and deprecations don't change, and the added test pins the ones no test covered yet. Instructions per operation (callgrind, -O2 build, arrays of 0/5/100 elements): new ArrayIterator() -181, i.e. -16.5%/-13.8%/-6.6%, and -11.4%/-4.7%/-0.4% when followed by foreach. new ArrayObject() -199, i.e. -17.8%/-14.9%/-7.2%, and -8.7%/-4.2%/-0.4% with foreach. offsetGet() and friends called as methods, e.g. via parent::offsetSet() in subclasses, are 39% to 43% cheaper. Walking Twig's node trees with foreach (17.6k nodes): -4.2% per round. The binary grows by 472 bytes of text. It's a sibling of #23945, which removes the array duplication that dominates the 100 elements case. Both touch spl_array.c and merge without conflict.